Direct Optical Resolution of Chiral Pesticides by High Performance Liquid Chromatography  

作　　者：LI Xiaogang LIU Yiping HU Changdi BAI Lianyang GAO Bida HUANG Kelong 

机构地区：[1]College of Bio-safety Science & Technology, Hunan Agricultural University, Changsha 410128, China [2]Hunan Institute for the Control ofAgrochemicals, Changsha 410005, China [3]Hunan Institute of Humanities, Science and Technology, Loudi 417000, China [4]Institute of Functionalized Materials & Chemistry, Central South University, Changsha 410083, China

出　　处：《Chinese Journal of Chemical Engineering》2011年第4期603-609,共7页中国化学工程学报（英文版）

基　　金：Supported by China Postdoctoral Science Fund (20090461007);Postdoctoral Research Funding Special Plans of Hunan(2010RC4025);Graduate Innovation Research Project of Hunan (CX2010B295)

摘　　要：Enantiomer separation is one of the most important prerequisites for the investigation of environmental enantioselective behavior for chiral pesticides.The enantiomeric separation of three chiral pesticides,indoxacarb,lambda-cyhalothrin,and simeconazole,were studied on cellulose tris-(3,5-dimethylphenyl-carbamate)-coated chiral stationary phase(CDMPC-CSP) using high-performance liquid chromatography under normal phase condition.The effects of chromatographic conditions,such as the mobile phase composition including the concentration and type of alcohol modifiers in hexane,flow rate and column temperature,on enantiomer separation were examined.The thermodynamical mechanism of enantioseparation and chiral recognition mechanism were discussed.Better separation were achieved using 20% n-propanol for indoxacarb,2% iso-butanol for lambda-cyhalothrin,and 20% iso-propanol for simeconazole as modifiers in hexane at 25℃ with the selectivity factor(a) of 1.69,1.82 and 1.70,respectively.The resolution factor(Rs) decreased as the flow rate increased from 0.4 to 1.1 ml·min-1.The retention factor(k') and selectivity factor for the enantiomers of analytes decreased as temperature increased.The lna-1/T plots for racemic chiral pesticides were linear in the range of 15-35℃ in hexane/iso-propanol and the chiral separation was controlled by enthalpy.Hydrogen bonding,π-π and dipole-dipole interactions between enantiomers and CDMPC-CSP play an important role in chiral identification,and the fitting of the asymmetric portion of solutes in a chiral cavity or channel of the CSP is also important.Enantiomer separation is one of the most important prerequisites for the investigation of environmental enantioselective behavior for chiral pesticides.The enantiomeric separation of three chiral pesticides,indoxacarb,lambda-cyhalothrin,and simeconazole,were studied on cellulose tris-（3,5-dimethylphenyl-carbamate）-coated chiral stationary phase（CDMPC-CSP） using high-performance liquid chromatography under normal phase condition.The effects of chromatographic conditions,such as the mobile phase composition including the concentration and type of alcohol modifiers in hexane,flow rate and column temperature,on enantiomer separation were examined.The thermodynamical mechanism of enantioseparation and chiral recognition mechanism were discussed.Better separation were achieved using 20% n-propanol for indoxacarb,2% iso-butanol for lambda-cyhalothrin,and 20% iso-propanol for simeconazole as modifiers in hexane at 25℃ with the selectivity factor（a） of 1.69,1.82 and 1.70,respectively.The resolution factor（Rs） decreased as the flow rate increased from 0.4 to 1.1 ml·min-1.The retention factor（k＇） and selectivity factor for the enantiomers of analytes decreased as temperature increased.The lna-1/T plots for racemic chiral pesticides were linear in the range of 15-35℃ in hexane/iso-propanol and the chiral separation was controlled by enthalpy.Hydrogen bonding,π-π and dipole-dipole interactions between enantiomers and CDMPC-CSP play an important role in chiral identification,and the fitting of the asymmetric portion of solutes in a chiral cavity or channel of the CSP is also important.

关 键 词：chiral resolution high-performance liquid chromatography INDOXACARB LAMBDA-CYHALOTHRIN simeconazole thermodynamical mechanism 

分 类 号：TQ450.1[化学工程—农药化工] O657.72[理学—分析化学]